The present invention relates to a method for chemically separating and enriching boron and uranium isotopes with high speed.
Boron-10 which is contained in an amount of 19.84% in natural boron and uranium -235 which is contained in an amount of 0.7196% in natural uranium are useful as a neutron absorber and a nuclear fuel, respectively.
As one of the methods for separation and enrichment of these boron and uranium isotopes, various proposals using ion exchanger have been made. However, in all of these methods, the difference in selectivity of the isotopes to an ion exhanger (separation factor) is very small and separation of the isotopes by ion exhanging becomes very difficult.
In order to separate such isotopes having extremely small separation factors to a satisfactory extent, the objective isotopes must be successively enriched by repeating the separation and enrichment operations many times. From the industrial view point, it is necessary to raise the separating efficiency per one operation or to raise the speed without lowering the separating efficiency. However, there is an inverse correlation between the separating efficiency and the increase of speed and so there is a limit in said method when ordinary ion exchange resins are used.
In view of such present circumstances regarding the technique of separating the isotopes by ion exchange method, the inventors have made intensive research to increase the separating efficiency and speed-up the separation to find that use of a fibrous weakly basic anion exchanger for separation and enrichment of boron and uranium isotopes provides favorable results. As a result, the present invention has been accomplished.